[Eosinophilic meningo-encephalo-myelitis due to Toxocara canis]

A 21-year-old woman was admitted to our hospital because of frontal headache, low-grade fever and convulsion. The patient had long been in a close contact with a dog. Neurologic examination revealed meningeal irritation signs and cerebellar ataxia. Slight leukocytosis with an increased rate of eosinophils (23.2%) was present. A lumbar puncture yielded 330 leukocytes/microliters with 30% of eosinophils; protein, 55 mg/dl; and increased IgG synthesis, 43.6 mg/day. The antibody titer against Toxocara canis was positive both in serum and in CSF by the use of immunoblotting assay, Ouchterlony, indirect immunofluorescence and ELISA. Cranial MRI showed a number of lesions located mainly cortically or subcortically, which had a hyperintense appearance on T2-weighted images and were clearly enhanced with Gd-DTPA. A diagnosis of eosinophilic meningoencephalo-myelitis due to Toxocara canis was made. In spite of the treatment with diethylcarbamazine and prednisolone, other lesions including cervical cord and optic nerves developed. Although CSF antibodies against Toxocara canis were reduced in titer, neurologic symptoms relapsed, raising the possibility that some allergic mechanisms may, at least in part, be responsible for this neurologic complication.